Exam 4 Practice Questions Flashcards
(123 cards)
1
Q
Describe the genome and symmetry of HAV
A
Single stranded positive RNA surrounded by naked icosahedral capsid
2
Q
THe 5’ end of the RNA strand of Hep A has a protein called _____.
A
VPg
3
Q
What is the most common transmission for hep A? Other modes of transmission?
A
Most common: oral-fecal
Other: sexual, IV drug use, blood borne
4
Q
Which hepatitis virus accounts for most of the hepatitis cases?
A
Hep A
5
Q
What is the pathology of Hep A?
A
Orally ingested -> enters bloodstream via GI lining -> migrates to the liver -> incubation period (prodrome) of 15-40 days -> sudden onset of symptoms -> recover in 8-12 weeks 99% of the time
6
Q
What are the symptoms of all hepatitis causing viruses?
A
Fever Headache Vomitting Jaundice Abdominal pain due to liver inflammation
7
Q
How is Hep A treated?
A
Prevention via proper sanitation and vaccination
8
Q
What is the most common mode of transmission for the hepatitis A virus?
Select one:
a. fecal-oral route
b. respiratory
c. IV drug use
d. sexual transmission
A
a. fecal-oral route
9
Q
Which of the following is true regarding hepatitis A?
Select one:
a. most people recover completely
b. most people develop chronic infection
c. some people develop chronic infection
d. IV drug use is the most common way to contract Hep A
A
a. most people recover completely
10
Q
Describe the genome and symmetry of HBV
A
incomplete DNA virus that is enveloped
11
Q
Serum hepatitis is referring to _____
A
HBV
12
Q
Infectious hepatitis is referring to _____
A
HAV
13
Q
HBV virons are also known as _______ _______
A
Dane particles
14
Q
What are the top three blood borne pathogens?
A
Hep B, Hep C and HIV
15
Q
What is unique about HBV replication?
A
The double stranded genome of HBV is completed by enzymes contained in the core of the virus after is enters the cytoplasm of the host cell
16
Q
How is HBV transmitted?
A
- Contact with body fluids (usually blood but can be vaginal secretions, menstrual blood, saliva and breast milk)
- IV drug use
- sexually
- neonate during birthing process
- tattoo, piercing, acupuncture
17
Q
What is the incubation period for HBV?
A
50-180 days
18
Q
What are the disease patterns of HBV?
A
If immune response is robust, it can be self limiting and resolve. If immune compromised, can result in chronic hepatitis leading to cirrhosis, liver cancer or liver failure
19
Q
How is severity of symptoms and probability of chronic infection related with HBV infection.
A
Inversely, meaning the fewer symptoms you have, the more likely you are to develop chronic infection
The younger you are, the fewer symptoms, the more likely chronic infection. Newborns are now being vaccinated
20
Q
How can an acute HBV infection be distinguished from a chronic HBV infection?
A
The presence of antibodies (IgM) against HBsAg
21
Q
How is HBV treated/prevented?
A
- Active or passive immunization
- avoid contact with blood or blood products
22
Q
What type of virus is hepatitis B?
Select one:
a. an incomplete DNA virus
b. a negative strand RNA virus
c. a positive strand RNA virus
d. a complete DNA virus
A
a. an incomplete DNA virus
23
Q
What is the most common way to acquire a hepatitis B infection?-
A
unprotected sex
24
Q
Individuals with chronic hepatitis B are at increased risk of: Select one: a. liver cancer b. respiratory infection c. lung cancer d. contracting hepatitis A
A
liver cancer
25
A vaccine is available for:
Select one:
a. Hepatitis B
b. Hepatitis C
c. HIV
HBV
26
Hep C is also referred to as _______
Non A, non B hepatitis
27
Describe the genome and symmetry of HCV
Positive strand RNA, enveloped, icosahedral
28
What are the known reservoirs of HCV?
Humans and chimps
29
What are the common modes of transmission for HCV?
- IV drug use (most common)
- blood transfusions
- sexual intercourse
- occupational exposure to blood
- tissue transplant
30
HCV is more resistant to ______ than HIV and can survive for several days on needles, etc.
Drying
31
Is HCV usually cleared or does it usually become chronic?
- usually becomes chronic. It is cleared in 15-25% of patients
32
Because HBV and HCV can be chronic, who can pass the virus on?
Any positive (HCV+ or HBV+) person
33
How is HCV diagnosed?
- Highly specific ELISA test, however the antibodies for this do not appear until 8-20 weeks after infection
- PCR can be used to detect RNA earlier
34
What is the treatment fo HCV?
- Ribivirin + interferon but this resolves only 50% of chronic HCV
- new, more effective medication available but too expensive to be widely used
35
A common route of transmission for hepatitis C is:
Select one:
a. IV drug use
b. fecal-oral
c. respiratory
d. direct contact
IV drug use
36
Hepatitis C, like other hepatitis viruses, target ________________.
Hepatocytes
37
Which of the following is true of hepatitis C?
Select one:
a. a vaccine is readily available
b. drug treatment is available
c. most recover without treatment
d. it can be passed through casual contact
b. drug treatment is available
38
What does it mean to say the HDV (aka Delta agent) is an incomplete virus?
It cannot code for its own surface proteins and therefore need a helper virus, HBV, to produce more virus particles
39
How is HDV transmitted?
Most commonly by IV drug use but also can be sexually transmitted
40
What are the typical symptoms of HDV?
HDV super infects an already HBV infected patient and causes acute hepatitis symptoms that resolve
41
How is HDV treated/prevented?
Prevent by vaccination for HBV, because HDV depends on HBV for productive infection
No treatment for HBV or HDV
42
Which of the hepatitis viruses are blood borne?
B, C, D
43
Which of the hepatitis viruses are transmitted but oral fecal route?
A, E
A can also be transmitted by direct contact, while E cannot
44
Describe the genome and symmetry of HEV
Positive strand RNA, naked, icosahedral
45
What is the incubation period for HEV?
16-60 days
46
Which hepatitis viruses have no chronic infections?
HAV and HEV
47
Can HEV or HAV be fatal?
Yes, but rarely
| Only in immune compromised/pregnant
48
Hepatitis D requires which other virus to infect liver cells?
Hep B
49
What is the route of transmission for the hepatitis E virus?
Fecal oral
50
Describe the genome and symmetry of the influenza virus
Single stranded RNA virus consisting of 8 RNA fragments, enveloped, spherical
51
What family does the influenza virus belong to?
Orthomyxoviridae
52
There are three types of influenza viruses, A,B,C. What determines whether a particular virus is A.B or C?
The internal antigens IM1 and NP)
53
Within the types of influenza viruses (A,B,C) there are subtypes that are determined by what?
External antigens of the viral envelope (HA and NA glycoproteins)
54
Major outbreaks are associated with what types of influenza virus and which has milder symptoms?
A and B, with B having milder symptoms
55
Which type of influenza virus is indistinguishable from the common cold?
Type C
56
What is type A so problematic?
It changes a lot every year and is found in both animals and humans
57
Which type of mutation in influenza virus results in a more rapid change, Antigenic drift or antigenic shift?
Antigenic shift
58
What occurs in antigenic shift?
New HA or NA glycoproteins are made. Internal antigens are unchanged
59
Where does the new HA and NA come from that causes antigenic shift?
An animal, usually a duck, becomes infected with both a human and animal influenza virus. Reassortment of the viruses occurs during replication, such that the internal components of the new virus are human and the HA and/or NA glycoproteins are from the animal virus
60
How is flu transmitted
Aerosolized particles from respiratory tract or infected surfaces
61
What is the incubation period fro influenzae?
24-48 hours
62
What is the pathogenesis of influenza?
Respiratory cells die due to effect of the virus. This causes cilia to also die, which reduces ciliary clearance or infectious agents from the respiratory tract.
63
What is Reye’s syndrome?
Rare encephalitis that follows certain viral infections (influenza and chicken pox), especially in children treated with aspirin
64
How is the flue treated?
Primarily by prevent with the annually formulated trivalent vaccine but some medication due exist (Tamiflu, relenza) that treat the flu
65
What is Guillain Barre syndrome?
Idiopathic disease in which the body damages its own nerve cells (outside CNS), causing muscle weakness and paralysis
66
Was is the relationship between Guillain Barre syndrome and influenza?
Guillain Barre syndrome was associated with vaccination with the swine flu vaccine in 1976
67
How does H5N1 influenza affect humans and animals?
- humans are infected by contact with duck or other infected bird, not each other
- Highly virulent and causes death in 6 out of 18 humans and most domestic poultry
- remains as a silent in ducks, making them a reservoir
68
Antigenic drift is due to:
Mutation
69
If in 2012 the major circulating strain of influenza was H3N2, and then in 2013 the major circulating strain was H1N1. How would you describe this change?
Antigenic shift
70
Which of the following groups is at highest risk of deaths due to influenza?
Select one:
a. the elderly
b. pregnant women
c. athletes
d. MSM (men who have sex with men)
Elderly
71
A child under the age of 12 with an influenza infection should not be treated with aspirin due to the risk of __________________.
Reye’s syndrome
72
How does Tamiflu function to help limit an influenza infection?
it prevents new viral particles from being released from host cells
73
Describe the genome and symmetry of picornaviridae
Positive strand RNA virus, naked, spherical, small
74
What is the most common disease pattern for those infected with poliovirus?
asymptomatic
Other patterns include:
- abortive
- non-paralytic
- paralytic
75
Non-paralytic polio is ____________________.
aseptic meningitis
76
What type of vaccine is the Salk vaccine for polio?
inactivated
77
What is the route of transmission for Coxsackie viruses?
fecal-oral
78
Which of the following is attributed to Coxsackie type A viruses?
Select one:
a. hand foot and mouth disease
b. myocarditis
c. pluerodynia
d. pericarditis
a. hand foot and mouth disease
79
What is the most common route of transmission for rhinovirus infection?
Respiratory
80
The virus that causes SARS is a typical ___________________.
Coronavirus
81
Deaths attributable to rotavirus are due to _________________.
dehydration
82
Symptoms of rotavirus infection include:
Select one:
a. watery diarrhea
b. cough and runny nose
c. pain on urination
d. ulcers in the oral cavity
watery diarrhea
83
Rabies virus enters at the site of the bite, moves to the dorsal root ganglion and then moves to the ______________.
Brain
84
Which of the following is a unique symptom of rabies infection?
Select one:
a. hydrophobia
b. photophobia
c. arachnophobia
d. claustrophobia
Hydrophobia
85
A diagnostic indicator of rabies infection is _____________.
Negri bodies
86
How is equine encephalitis virus transmitted?
Mosquito
87
West Nile virus is vectored by the _____________.
Mosquito
88
Most individuals infected with the West Nile virus ________________.
Are asymptomatic
89
What is the vector for the yellow fever virus?
Mosquito
90
A vaccine is available for which of the following viruses?
Select one:
a. ebola
b. yellow fever
c. dengue fever
d. West Nile
Yellow fever
91
Dengue fever is characterized by which set of symptoms below?
Select one:
a. fever and muscle/bone pain
b. cough and runny nose
c. pain on urination and ulcers
d. severe bleeding and pain
fever and muscle/bone pain
92
Having had dengue fever, a second infection with a different version of the virus is likely to result in _____________________.
hemorrhaging from many body locations
93
What is the vector for the chikungunya virus?
mosquito
94
When did the chikungunya virus first emerge in the Americas?
2013
95
Which of the following is a zoonotic virus (virus acquired from a non-human animal source)?
Select one:
a. West Nile
b. hantavirus
c. yellow fever
d. lassa fever
hantavirus
96
How is the ebolavirus transmitted?
via contact with infected blood
97
Which of the following enzymes must a retrovirus bring with it as it infects a human cell?
Reverse transcriptase
98
HTLV viruses can induce _____________ in human cells.
Cancer
99
HIV-1 is most closely related to _____________.
SIV cpz
100
HIV-2 is most closely related to _____________.
SIV sm
101
What is the most common subtype of HIV-1 in North America and Europe?
B
102
Which part of the HIV virus interacts with the CD 4 receptor on a T cell?
GP 120
103
Which enzyme allows the DNA of HIV to enter the host's DNA?
Integrase
104
After HIV binds to GP 120 what must happen for the virus to enter the host cell?
a co-receptor must be bound
105
How does HIV exit a T lymphocyte?
lysis of the host cell
106
What enzyme is responsible for liberating other enzymes (Gag-Pol) during the assembly of new HIV virions?
protease
107
Which of the following is NOT a possible route of transmission for HIV?
Select one:
a. contaminated needles
b. sex with an infected individual
c. a mosquito bite
d. a blood transfusion
a mosquito bite
108
During sexual transmission of the virus, what cell first interacts with the HIV virus in the susceptible partner?
dendritic cell
109
When would you anticipate an HIV+ patient having the highest titer of virus?
4-10 days after infection
110
If an individual tests negative for the HIV virus 2 weeks after an occupational exposure should she be considered definitely HIV-?
No
111
The period of time during which T cell destruction is balanced by appropriate immune response and production of additional T cells is termed _____________.
Dynamic equilibrium
112
What defines the onset of AIDS?
onset of opportunistic infections
113
What, in part, helps explain the variation seen in the HIV virus within a single patient?
high mutation rate of reverse transcriptase
114
Drug resistance seen in some HIV strains is due, partially, to:
Mutation
115
The majority of HIV+/AIDS patients reside in _____________.
Africa
116
Currently in the US, which group represents the highest number of HIV diagnoses?
MSM (men who have sex with men)
117
Which of the following carries the highest risk of exposure to health care workers?
Select one:
a. needle stick
b. blood in the mouth
c. a paper cut
d. blood in the eyes
Needle stick
118
What is the most commonly used test for HIV diagnosis?
ELISA, although PCR can also be used
119
The highest titer of HIV can be expected in which of the following patients?
Select one:
a. AIDS patients
b. patients with a T cell count of 400/cc of blood
c. patients that have been HIV+ for 2-5 years
d. patients that have been HIV+ for 10 or more years
AIDS patients
120
The first HIV drug that was released to market was AZT, what type of drug is AZT?
reverse transcriptase inhibitor
121
To best preserve T cell function, HIV+ patients typically:
take a combination of anti-retroviral drugs
122
Which type of vaccine would be the safest for vaccinating for HIV?
Subunit, although not super effective
123
True or false. A vaccine to prevent HIV is currently available as of summer 2016.
False, Many vaccines have been developed, but none are approved or available.
